1. Field of the Invention
The invention relates to a suction and covering device for suctioning ink from ink jet print heads of an ink jet print unit and for sealing the print heads including elastic cups, pressure compensation channels, suction channels, and a valve device.
2. Brief Description of the Background of the Invention Including Prior Art
Ink jet printing devices are of increasing interest for the user based on the development of ever more powerful and increasingly higher capability microprocessors in addition to a plurality of other print devices such as, for example, pin printers, matrix printers, thermal transfer printers, thermal printers, thermographic printers, and electrophotographic printers. The purchase of a printer is frequently a complex decision, where the production features such as speed, economy and print quality are in the foreground based on the increased capability of the peripheral text processing apparatus. The production feature, namely to be able to print in color, is furthermore of marked importance for various fields of application. For this purpose, ink printing presents optimum preconditions and prerequisites based on the use of color writing liquids, which can be produced at a low cost and in a simple manner, in addition to the thermal transfer printing process.
The ink colors employed for providing color to the writing liquids are, for example, yellow, cyan, magenta, and black according to the German printed patent document DE-A1 37 36 916. The ink in the nozzle exit openings of an ink jet print head can dry up in case of longer printing intervals. In order to prevent this drying, the ink jet print device exhibits, for example, a cleaning and sealing station or, respectively, a suction regeneration device. Cleaning and sealing stations can also be employed to eliminate soiling at the nozzle exit openings of the ink jet print head in the ink jet print device. For this purpose, the ink jet print heads are cleaned at regular time intervals and are sealed in case of longer printing intervals of the ink jet printing device. The cleaning and sealing station exhibits for this purpose a suction and covering device.
If such suction and covering devices are employed in color printers, then the danger arises that ink fluids of different colors are mixed during cleaning and sealing in the area of the nozzle ejection openings and this results in interferences and disturbances of the print image, and this causes unnecessary downtimes of the print devices and requires additional cleaning processes.
In general, an ink meniscus at the nozzle ejection openings prevents entry and penetration of air into the ink supply region of the ink jet print heads in print devices, which operate according to the negative pressure principle. The suction and covering devices can destroy such block menisci by pressing air into the ink jet ejection openings. This requires additional ventilation procedures under certain circumstances.
A cleaning and sealing station or, respectively, a suction regeneration device for ink jet print heads in ink jet print devices is known in each case from the German printed patent document DE-A1-33 16 474, German printed patent document DE-A1-33 16 968, German printed patent document DE-A1-36 04 373, German printed patent document DE-A1-36 11 333, German printed patent document DE-A1-36 33 239, German printed patent document DE-A1-37 26 671, German printed patent document DE-A1-38 10 698, and European printed patent document EP-A1-0,094,220. Nozzle exit openings of the ink jet print heads are cleaned, flushed and the nozzle exit openings are sealed in case of longer printing intervals of the ink jet print devices in different ways with the cleaning and sealing station or, respectively, the suction regeneration device.